Tracking or detecting the presence or removal of retail items from an inventory or retail establishment comes under the venue of electronic article surveillance (EAS) and radio frequency identification (RFID). EAS or RFID detection is typically achieved by applying an EAS or RFID element as part of a security tag to an item or its packaging. When the security tag is exposed to a predetermined electromagnetic field, such as those generated by gates at a retail establishment exit, the tags activate to enable an alert and/or supply data to a receiver or other detector.
It has become desirable to include an EAS and RFID element on, or in, a single security tag wherein each security element responds to a different interrogator/reader system. Such a security element may be known as a dual EAS-RFID tag. For example, it may be desirable to read the RFID element of a tag attached to an article for inventory purposes while also having the capability to interrogate the EAS element if the tagged article should be removed from a store exit without having been purchased. Commonly-owned U.S. Pat. No. 8,026,818 entitled “EAS and UHF Combination Tag” provides examples of tags comprising both an EAS and an RFID element, e.g., dual EAS-RFID tags. This reference is incorporated by reference herein.
While dual EAS-RFID tags exist, they are typically large. Previous attempts to reduce the size of dual RFID-EAS tags have resulted in performance being compromised such that, at longer distances, the tag can be read within only a narrow band of frequencies. Thus, there exists a need for a dual EAS-RFID tag that is small in size without sacrificing the performance of the RFID or EAS element.